The Way That I Cast – The Lost Wax Process

I have had several folks ask me questions lately about how I cast my pieces for my shop, so I decided that it was time for a brief explanation and some pictures of my shop.

The process that I use for the majority of my cast pieces is called Lost Wax. It all starts with waxes. The picture below shows a few waxes that have been molded and could be turned into metal pieces. The different color waxes indicate that the wax has different characteristics. The blue wax is more brittle, but it is much better for carving. I often use this wax if I am going to repair a wax that was created from a mold of an original artifact. The details on the original may have been damaged by the ravages of time, and need some fine tuning, or there may be a broken loop or other needed repair.


These waxes were created by injecting wax into an existing mold. They can also be made by carving a piece of wax to create an original master. I rarely use a wax master  when I cast. Instead I make a mold of that wax and use the mold to create copies of the master. This avoids the problem of having a failed casting attempt destroy your wax master, which usually takes quite a while to create. Here is a picture of the wax injector that I use for most of my wax casting.

Wax pot and molds

As you can tell from the drips, this wax injector contains red wax. It requires an air compressor to provide the “push” to inject the wax into the mold. The wire shelves contain an assortment of wax molds. The differences in color indicate that they are made out of different molding compounds. The green molds are made using RTV – Room Temperature Vulcanizing Silicone. That compound will harden to form a mold at most normal room temperatures. The tan molds have to be cooked in a special machine, called a Vulcanizer, in order to harden. The odd looking contraptions on the table to the left of the wax injector (with handles that look like drawer pulls) are special mold clamps that provide a reliable and steady amount of pressure on the outsides of the molds for when you want to inject them with wax. An improperly clamped mold will allow hot wax to squirt out all over. Since the wax is between 150 and 160 degrees Fahrenheit, this is both messy and a bit painful to get on your skin.

This is a picture of a Vulcanizer. The mold material, with the metal model inside, is placed in a frame between two sheets of metal, and clamped between the jaws of the Vulcanizer. The thermometer is used to double check the exact temperature of the jaws before the mold compound is put in place. The mold is allowed to cook for between 20 minutes and several hours, depending on the thickness of the mold and the type of molding compound being used.


Next Time: So now that we have waxes, what next? We turn the waxes into a mold!


Dealing with Sterling Silver Jewelry Shapes that are Difficult To Polish

Dealing with sterling silver jewelry shapes that are difficult to polish can be challenging.

Yesterday I was working on a large sterling silver jewelry project – a coronet for a friend who is a historic re-enactor. There are a LOT of differences between working on small pieces of jewelry, and working with something this large. And that reality prompted me to make a couple of quick tools to make the polishing safer and more effective.  As I was working, I realized that a couple of the things that I had figured out might be of use to others, so here are two quick tips for polishing large objects.

The sterling silver jewelry piece that I was working on was challenging because it was large with lots of pointy bits that made it waay too dangerous to polish on a big polishing wheel. The opportunity for it to catch in the wheel and either do damage to me or the piece was a serious concern. So that meant it was time to haul out the flex shaft for finishing! But how to hold and polish the piece at the same time? The piece is essentially a large oval, made from a strip of sterling silver one inch wide and 25 inches long. The band is decorated with sterling silver annulets (think donut shapes) and a specialized form of a sterling silver cross with a pointy bottom and exaggerated pointy arms. The annulets are completely soldered flat to the band, but the crosses stick up above the top of the band with all of their pointy goodness just waiting to hook onto any polishing wheel that comes near them. I often polish smaller pieces by simply holding them in my hand, but that was NOT going to work for this large piece of sterling silver jewelry (well it’s more of an accessory than what we think of as jewelry). I am fortunate enough to have a jewelers’ bench in my Studio, so I put padded bench pinthe bench pin into the front of the bench. Now for those of you who don’t have something like a bench pin, well, I would probably lay a chair down on the floor on its side, sit on the floor or a stool, and use one of the legs as a support. The chair leg can serve the same function as a bench pin in this application.

I always have a pile of those white terry cloth shop towels in my Studio. They are inexpensive, and handy for everything from spills to padding, which is exactly what I used one for! I folded the towel in half, wrapped it around the bench pin   and then held it in place with some masking tape. Now I had a clean, slightly rounded and padded, non-scratch support (a temporarily modified bench pin) that I could rest my massive sterling silver jewelry on for polishing. If I were using a chair leg, the towel would protect the chair and give the same kind of padding ( I would NOT do this with grandma’s valuable antique chair, just in case). The piece, remember it is a large oval, could literally hang on the towel-covered bench pin (or chair leg) and easily be held in place with one hand while I polished it with the other. There is another seriously important aspect to this arrangement. When it coronet on padded bench pinwas time to polish the tops of the sterling silver crosses, even the flexshaft wanted to hook onto and dance around the piece. Solution? Press the top of the crosses down into the towel just slightly. The polishing buff could easily do its job on the front of the crosses without catching the edge of the piece. It does get the towel dirty, but that is what those towels are for – they are called shop towels for a reason!

My goal when I whipped up this quick little modified bench pin support was three-fold – protect me, protect the piece, and allow me to polish the piece until the sterling silver gleamed. Mission accomplished! I hope this gives you some ideas for making your own workshop safer and more productive! I’ve included a picture so you can see my “high-tech” support system and what the sterling silver piece looked like while it was being polished. Enjoy!

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